Ventricular Assist Device

ABSTRACT

A ventricular assist device for use in a human recipient includes a housing within which a series pair of turbine pump segments and at least one set of deswirlers are operative. The series pair of turbine pump segments provides a redundancy in turn enhances the safety factor provided by the ventricular assist device. A controller is powered by a rechargeable battery and is operative to apply appropriate drive signals to the motor drives of the turbine pump segments. The battery may be implanted along with the controller to avoid the need for any external connections to the ventricular assist device. An inductively coupled battery charger for use outside the recipient&#39;s body is positioned proximate the battery charger to provide inductively coupled charging for use in driving the ventricular assist device.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a Continuation of previously filed and co-pending U.S. application Ser. No. 16/132,304 entitled VENTRICULAR ASSIST DEVICE, filed Sep. 14, 2018, which is a Continuation-In-Part of U.S. Pat. No. 10,286,134 entitled VENTRICULAR ASSIST DEVICE, filed Jan. 12, 2017 in the names of Peter DeSilva and Steve Smith.

FIELD OF THE INVENTION

This invention relates generally to apparatus for sustaining and continuing life for patients having failing or failed hearts and particularly to artificial devices, known generally in the art as “Ventricular Assist Devices” (VADs), including ventricular assist devices such as “Left Ventricle Assist Devices” (LVADs) also used to supplement the performance of weak or failing hearts. This invention also further relates to U.S. Pat. No. 9,314,559, issued to Steve Smith and Peter DeSilva, entitled FOUR CHAMBER REDUNDANT-IMPELLER ARTIFICIAL HEART, the disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

For many years, practitioners in the medical treatment and medical device arts have endeavored to provide artificial heart devices constructed to replace a failed or failing heart within a patient recipient. The most basic long term need is the creation of a replacement pumping device which is capable of performing the basic blood pumping and circulation functions of the natural heart.

Early attempts to provide a sustainable heart replacement were severely limited by the available technologies and the state of the art at that time. Devices proved to be generally too large and unwieldy and, for the most part, impractical. With the continuing advances in the related technologies and creative arts, heart replacement devices became smaller, more reliable and, in some instances, at least partially implantable within the recipient. Such “implantable” devices have generally remained hybrid devices in that the actual pump may be implanted within the recipient while additional support apparatus remains external to the patient and remains connected to the implanted device by a plurality of connecting wires and hoses.

One of the more recent attempts to provide a reliable and practical artificial heart device which embodies great promise, is shown in the above-referenced and incorporated U.S. Pat. No. 9,314,559 which sets forth an artificial heart for use in a human recipient that includes a housing within which a quartet of turbine pump segments are operative. The quartet of turbine pump segments provides a redundancy which in turn enhances the safety factor provided by the artificial heart. A controller is powered by a rechargeable battery and is operative to apply appropriate drive signals to the motor drives of the turbine pump segments. The battery may be implanted along with the controller to avoid the need for any external connections to the artificial heart. An inductively coupled battery charger for use outside the recipient's body is positioned proximate the battery charger to provide inductively coupled charging for use in driving the artificial heart.

In a field of endeavor closely related to the attempts to provide a practical and reliable implantable artificial heart, practitioners have also been addressing the need for a ventricular assist device. Such ventricular assist devices (VADs) supplement the performance of a weakened heart without fully replacing it. Ventricular assist devices provide an implantable mechanical pump that helps blood flow from the lower chambers of a weakened heart, the ventricles, to other parts of the body or other parts of the heart itself. One of the most prevalent uses of such ventricular assist devices, known as a left ventricular assist device LVAD, is implanted in the patient's chest cavity and is used to pump blood from the lower portion of the left ventricle to the heart aorta.

A successful ventricular assist device must, above all, be long lasting and reliable. The dire consequences to the device recipient brought about by device failure make this requirement all too apparent. In addition, however, the device must be small enough to be implantable within the recipient's chest and efficient enough to maintain adequate blood circulation to sustain normal life functions. The device must avoid undue stress upon the recipient's circulatory and pulmonary systems. The device must also be capable of adjusting to and compensating for different recipient activity levels and stresses. Additional requirements such as avoidance of turbulence within the blood flow, blood cell damage by the pumping apparatus and the prevention of blood clot forming stagnation regions make further demands upon ventricular assist devices.

A substantial number of recently explored technologies attempting to provide successful implantable ventricular assist devices have chosen to utilize pumping apparatus which includes a rotating impeller such as a turbine impeller or the like. While rotating turbine impeller type pumps have shown great promise for ventricular assist devices, a limitation has arisen which takes the form of rotational blood flow turbulence created by the rotating impellers of the turbine pumps. This turbulence has been found to exhibit vortex characteristics which are undesirable in application to blood pumping apparatus.

In a related art, various apparatus have been provided for reducing or mitigating the turbulence within fluid flow systems induced by the rotating pumps such as turbine pumps or the like. Such apparatus are often referred to in the art as “deswirlers” or “flow straighteners”. Such devices are typically placed downstream in the fluid flow relative to the rotating pump elements with the object of counteracting the rotational turbulence component in the flow produced by the rotating pump elements. In one such element a type of “fluid collimator” is provided in which a plurality of generally small fluid passages are arranged in a parallel relationship much like a box of drinking straws. In another type of deswirler device, a plurality of vanes are situated within the fluid flow downstream of the rotating pump element.

Thus, while practitioners in the medical treatment and medical device arts have created a virtually endless number of proposed artificial ventricular assist devices, there remains nonetheless a continuing unresolved need in the art for an improved, implantable, reliable and effective artificial ventricular assist device which meets the stringent, unforgiving and vital requirements and challenges posed by a truly fully functioning completely implantable ventricular assist device.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide an artificial ventricular assist device which is reliable, implantable and effective. It is a more particular object of the present invention to provide an improved ventricular assist device which avoids the need for external component apparatus and which signals events or anomalies within the system while shifting to backup remedial life sustaining operation.

It is also a general object of the present invention to provide an artificial ventricular assist device which is reliable, implantable and effective. It is a more particular object of the present invention to provide an improved ventricular assist device which avoids the need for external component apparatus. It is a still more particular object of the present invention to provide an artificial ventricular assist device which eliminates, or substantially minimizes, rotational turbulence or vortex creation within the blood flow.

In accordance with the present invention, there is provided a ventricular assist device comprising: a housing having an input connector and an output connector, a first turbine pump operative to flow blood from the input connector to the output; a second turbine pump operative to flow blood from the input connector to the output connector.

Also in accordance with the present invention, there is provided a ventricular assist device comprising: a housing having an input connector and an output connector, a first turbine pump operative to flow blood from the input connector to the output connector; a first deswirler located downstream of the first turbine pump; a second turbine pump operative to flow blood from the input connector to the output connector; a second deswirler located downstream of the second turbine pump wherein the first and second deswirlers are operative upon the blood flows from the first and second turbine pumps respectively to reduce or eliminate rotational turbulence or vortex blood flow due to the rotations of the turbine pump impellers.

From another perspective, the present invention provides a ventricular assist device comprising: a housing having an input, an output, a first turbine pump operative to flow blood from the input to the output; a second turbine pump operative to flow blood from the input to the output. In a preferred fabrication of the present invention ventricular assist device, the first and second turbine pumps are arranged in series pairs within the blood flow. The turbine pumps are supported within a housing defining a straight-through blood flow path, supporting the series pair of turbine pumps.

From another perspective, the present invention provides a ventricular assist device comprising: a housing having an input, an output, a first turbine pump and first deswirler operative to flow blood from the input to the output; a second turbine pump and second deswirler also operative to flow blood from the input to the output. In a preferred fabrication of the present invention ventricular assist device, the first and second turbine pumps are arranged in series pairs within the blood flow. In one embodiment, the first and second turbine pumps and their respective deswirlers are operative within a curved generally U-shaped blood flow passage. In an alternate embodiment, the first and second turbine pumps and their respective deswirlers are supported within a housing defining a straight-line blood flow path.

The present invention improves the art by providing a dual stage redundant impeller ventricular assist device. Within the housing a pair of electrically driven impeller drive motors facilitate the pumping of blood from one portion of the circulatory system to another portion of the circulatory system, such as from the lower left ventricle to the aorta. The use of dual pump drives for the pump turbines is configured to provide complete pump redundancy should a pump fail. In such case, the remaining operative motor/pump drives the turbines coupled thereto with sufficient capability and circulation to maintain life in the recipient until remedial intervention may be performed. The output from the pump supports a sensor coupled to a dual microprocessor drive controller. Each microprocessor drive controller is operatively coupled to both of the redundant pump drive motors. Sensors are also provided to monitor the operation of each pump system. A pair of battery modules each including an inductively coupled charging device are implanted within the patient abdomen and operatively coupled to the processor controller and the drive motors. A pair of inductive battery charging modules are supported upon an abdominal belt and coupled to a source of operative electrical power. Battery charging is accomplished by inductive coupling through the body tissue between the external charging modules and the implanted battery and charger apparatus. The dual redundant micro controller is also implanted within the recipient's body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 sets forth a perspective view of a ventricular assist device constructed in accordance with an embodiment of the present invention;

FIG. 2 sets forth a side elevation view of a ventricular assist device constructed in accordance with the present invention;

FIG. 3 sets forth an end view of a ventricular assist device constructed in accordance with the present invention;

FIG. 4 sets forth a depiction of a ventricular assist device constructed in accordance with the present invention operatively coupled to a human heart;

FIG. 5 sets forth a system diagram of a ventricular assist device constructed in accordance with present invention installed within and upon an illustrative human recipient;

FIG. 6 sets forth a section view of a ventricular assist device constructed in accordance with present invention;

FIG. 7 sets a perspective view of an alternate embodiment of the present invention ventricular assist device;

FIG. 8 sets forth a side elevation view of the alternate embodiment of the present invention ventricular assist device set forth in FIG. 7;

FIG. 9 sets forth a front view of the alternate embodiment of the present invention ventricular assist device show in FIG. 7;

FIG. 10 sets forth a depiction of a ventricular assist device constructed in accordance with the alternate embodiment of the present invention set forth in FIG. 7 operatively coupled to a human heart;

FIG. 11 sets forth a system diagram of a ventricular assist device constructed in accordance with the alternate embodiment of the present invention set forth in FIG. 7 installed within and upon an illustrative human recipient;

FIG. 12 sets forth a section view of the alternate embodiment of the preset invention ventricular assist device set forth in FIGS. 7; and

FIG. 13 sets forth a section view of a still further alternate embodiment of the present invention ventricular assist device illustrating an angular coupling passage and angularly disposed turbine pumps.

FIG. 14 sets forth a section view of another embodiment of a ventricular assist device constructed in accordance with the present invention;

FIG. 15 sets forth a section view of another alternate embodiment of the present invention ventricular assist device shown in FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 sets forth a perspective view of a ventricular assist device constructed in accordance with the present invention and generally referenced by numeral 10 ventricular assist device 10 includes a generally cylindrical housing 11 supporting a pair of end caps 12 and 14. End cap 12 further supports and input connector 13 while end cap 14 further supports an output connector 16. A pair of output flow “pressure” sensors 15 and 17 are supported upon output connector 16. In its preferred fabrication, housing 11 and end caps 12 and 13 together with connectors 15 and 16 are formed of a medically approved suitable molded plastic material or the like. By operation set forth below in greater detail, ventricular assist device 10 is operative to pump a flow of blood coupled to input connector 13 through housing 11 to exit at output connector 16.

As is better seen below in FIG. 2, conventional hose connectors 20 and 21 are coupled to input connector 13 and output connector 16 respectively to provide blood flow which is pumped through ventricular assist device 10. It will be apparent to those skilled in the art that the small compact generally cylindrical shape of ventricular assist device 10 is well adapted to being implanted within a recipient's chest cavity in the manner shown in FIG. 4.

In operation, a pair of turbine pumps described below, are operative within ventricular assist device 10 to provide blood flow from hose 20 through housing 11 and outwardly through hose 21 as represented by directional arrow 22. As is set forth and described below in greater detail, a pair of turbine pumps arranged in a series configuration are operative to provide blood flow and, due to the redundancy of turbine pumps, also provides enhanced reliability. In the general design considerations under which ventricular assist device 10 is fabricated, either turbine pump has sufficient capability to be operated to produce a blood flow rate sufficient sustain the life of the ventricular assist device recipient. As described below, pressure flow sensors 15 and 17 are operatively coupled to the controller shown in FIG. 5 to provide operational monitoring of ventricular assist device 10. Flow sensors 15 and 17 operate to sense the blood flow outwardly through output passage 21 for monitoring performance of ventricular assist device 10.

FIG. 3 sets forth an end view of the ventricular assist device 10 showing the concentric arrangement of cylindrical housing 11 and end cap 14. While not seen in FIG. 3, it will be understood that the opposite end of ventricular assist device 10 is substantially identical to the end view shows in FIG. 3. FIG. 3 also shows the position of output connector 16 upon end cap 14. The generally concentric arrangement of housing 11, end cap 14 and output connector 16 provides the highly desirable “straight-through” blood flow provided by the redundant turbine pumps within ventricular assist device 10.

FIG. 4 sets forth a depiction of ventricular assist device 10 coupled to an illustrative human heart generally referenced by numeral 30. Human heart 30 includes a left ventricle 31 and aorta 36. In the application of ventricular assist device 10 shown in FIG. 4, ventricular assist device 10 is functioning as a left ventricle assist device. The input of ventricular assist device 10 is coupled to the lower portion of left ventricle 31 at a coupling 32 using a hose 20. A hose 21 is coupled to the output connector of ventricular assist device 10 and coupled to aorta 36 of heart 30 at a coupling 33. Couplings 32 and 33 are achieved utilizing conventional medical techniques to provide effective blood transfer and to prevent leakage and other problems. Similarly, hoses 34 and 35 are fabricated of a medically of approved flexible hose construction and may be entirely conventional in fabrication.

In operation, heart 30 will be understood to be beating and attempting to pump blood from left ventricle 31 to aorta 36 and from there outwardly through the arteries of the patient's body. In a typical use of a ventricular assist device performing in the role of a left ventricle assist device shown in FIG. 4, left ventricle 31 is, for some reason, underperforming and an adequate supply of blood is not being pumped into aorta 36. The benefit provided by ventricular assist device 10 in its role as a left ventricle assist device is to provide a supplemental blood flow from left ventricle 31 through hose 20 to ventricular assist device 10. As ventricular assist device 10 is operated blood is pumped in the direction indicated by arrow 22 which is carried by hose 21 to coupling 33 and thereafter flows into aorta 36. This is the basic left ventricle assist performance which greatly improves the blood supply and blood flow for the host patient despite the underperformance of left ventricle 31, or other causes of heart underperformance. In accordance with an important aspect the present invention, increased reliability is provided by ventricular assist device 10 due in part to the redundant dual turbine pump arrangement.

FIG. 5 sets forth a system diagram of the present invention ventricular assist device 10 together with supporting apparatus depicting the installation of ventricular assist device 10 within a host patient's body. In the situation represented in FIG. 5, ventricular assist device 10 has been implanted within a host patient's body and is operatively coupled in the manner set forth above in FIG. 4 to the host patient's heart to provide a left ventricle assist device. FIG. 5 further shows microcontroller unit 140 also implanted within the host patient's body. Microcontroller unit 140 is formed of a pair of fully redundant micro controllers 141 and 142. The redundancy of microcontrollers 141 and 142, each able to fully support the operation of ventricular assist device 10, provides a further measure of reliability. Microcontroller unit 140 further includes conventional apparatus (not shown) for communicating to the exterior of the host patient's body in order to provide alarm condition information or other required maintenance of monitoring information to an external unit (not shown).

As described above, ventricular assist device 10 includes a pair of flow sensors 15 and 17 situated at the output of ventricular assist device 10. Flow sensors 15 and 17 are coupled to redundant microcontrollers 141 and 142. Microcontroller 142 further includes additional sensors supported within ventricular assist device 10 for monitoring the performance of the servo drive apparatus therein. A pair of battery units 150 and 160 are also implanted within the host patient. Battery unit 150 includes a secondary charging coil 151 coupled to a rectifier 152 which, in turn, is coupled to a battery 153. Battery unit 150 is coupled to microcontroller 141. Similarly, battery unit 160 includes a charging coil 161 coupled to a rectifier 162 which, in turn, is coupled to a battery 163. By way of further similarity, battery unit 160 is operatively coupled to microcontroller 142. Thus, microcontroller unit 140, ventricular assist device 10 and battery units 150 and 160 together with appropriate wire connections therebetween are implanted within a host patient body. For purpose of illustration, FIG. 5 shows body segments 118 and 119 which represent the skin and associated tissues of the host patient body beneath which battery units 150 and 160 are implanted. Preferably, units 150 and 160 are implanted near the host patient's midsection and preferably situated just beneath the patient's skin.

A charging belt 158 suitably configured to be worn by the host patient such as at or near the patient's waist supports a pair of charging units 155 and 156. Charging units 155 and 165 include respective primary charging coils 156 and 166. Coils 156 and 166 are coupled to source of alternating current power such as a conventional electrical outlet 145 via a conventional coupling adapter 146.

In operation, micro controllers 141 and 142 monitor sensors within ventricular assist device 10 and provide suitable operating power and control to the servo drives supported therein (seen in FIG. 6). Microcontrollers 141 and 142 utilize batteries 153 and 163 for operative battery supply and for power to energize the servo drive apparatus within ventricular assist device 10. The operative power stored within batteries 153 and 163 is provided by inductive charging utilizing charging units 155 and 165. Thus, during convenient periods, the host patient utilizes charging belt 158 by coupling it to power source 145 while wearing belt 158 such that primary charging coils 156 and 166 are positioned on the outside of body portions 118 and 119 respectively. Also, a general alignment is obtained between primary charging coils 156 and 166 and secondary coils 151 and 161 respectively. Electrical power is then inductively coupled through body portions 118 and 119 to induce alternating current power within secondary coils 151 and 161. Rectifiers 152 and 162 convert the alternating current induced in coils 151 and 151 to a direct current power suitable for charging batteries 153 and 163. In this manner, the user is able to replenish the battery energies as required by simply wearing charging belt 158 for a suitable time interval.

Micro controller unit 140 functions using a pair of fully-redundant fully-interconnected micro controllers 141 and 142, each having the complete capability to control and run ventricular assist device 10 and it's monitoring and charging functions. Thus, microcontrollers 141 and 142 provide inputs for two batteries, inputs for multiple pressure and Hall effect servo sensors and systems capable of monitoring multiple battery charge levels and switch between batteries. The redundancy of microcontrollers 141 and 142 includes configuration of the system such that each microcontroller “sees” all its own inputs and also “sees” all inputs to the other microcontroller. This redundancy includes each microcontroller being capable of making compensating performance adjustments to maintain envelope system performance. However, to avoid “hunting” between the redundant microcontrollers, it is preferred that small pressure variations of each pump be allowed before adjustment is made.

Micro controller unit 140 further includes communication capability, such as a wireless unit, to call, or text remote locations to indicate system anomalies, failures, operating conditions, battery charge levels and other conditions. In addition, microcontroller unit 140 provides the capability to adjust each of microcontrollers 141 and 142 based on pressure readings and to set and maintain preset maximum and minimum pressure envelopes. Microcontroller unit 140 also provides the ability of replicating the pulsatile characteristic of a normal human heart by introducing pre-programmed increases and decreases of pump speed to create pressure surges and lulls.

FIG. 6 sets forth a section view of ventricular assist device 10. Ventricular assist device 10 includes a pair of turbines 55 and 65 in a series arrangement. Turbine 55 is preferably fabricated to provide a helical blade that is progressive to form a helix. Turbine 55 further supports a cylindrical magnetic rotor 56 which is joined to the outer edges of turbine 55. Magnetic rotor 56 supports a plurality of permanent magnets and together with turbine 55 forms a single preferably integrally fabricated rotating component. Thus, for example, it will be recognized that while turbine 55 may be precision-fitted within magnetic rotor 56 due to the cylindrical structure of magnetic rotor 56 thereby forming a single rotating unit, in the preferred fabrication of the present invention magnetic rotor 56 is integrally formed and molded with turbine 55. In either event, it will be recognized that the combined structure of turbine 55 and magnetic rotor 56 forms a single integral rotating unit. The combined structure of magnetic rotor 56 and turbine 55 are rotatably supported within the interior of housing 11 by a pair of bearing supports 57 and 67 positioned on each side of the rotating turbine element. The structure of bearing supports 57 and 67 includes center hubs 58 and 59 supported by a plurality of spokes 70, 71 and 72 (spoke 72 not shown). Within hub 58, a bearing cup 54 is supported which in turn receives one end of a bearing pin 53.

Bearing support 67 is identical to bearing support 57 and thus includes a center hub 59 which receives a bearing cup 64 and bearing pin 63. During assembly, bearing support 67 receives bearing cup 64 and is inserted in turbine receptacle 80 formed in housing 11. Thereafter, bearing pins 64 and 63 are inserted into the support shaft of turbine 55. The combined structure of turbine 55 supporting bearing pins 63 and 64 together with magnetic rotor 56 is then inserted into turbine receptacle 80. Bearing support 57 is then fitted within turbine receptacle 80 such that bearing pin 53 is received within bearing cup 54. Turbine 65 is similarly assembled within turbine receptacle 90. Once both turbine and magnetic rotor combinations have been assembled within housing 11, end caps 12 and 14 are joined to center housing 11 using an attachment such as thermal or sonic welding or other appropriate attachment. Once end caps 12 and 14 are assembled to center housing 11, the structure of ventricular assist device 10 is complete and the resulting pump structure may be described.

More specifically, ventricular assist device 10 includes a center housing 11 defining a pair of turbine receptacles 80 and 90. Receptacles 80 and 90 are aligned coaxially and define cylindrical receptacles. Turbine receptacles 80 and 90 are coupled by a venturi coupling passage formed by a tapered portion 81, a center passage 79 and a tapered portion 91 which are also generally coaxial with turbine receptacles 80 and 90.

Housing 11 further supports a generally cylindrical drive coil array 85 which encircles turbine receptacle 80. Drive coil assembly 85 is coupled to a motor controller such as controller 140 as set forth above and in FIG. 5. Similarly, housing 11 supports a corresponding drive coil 95 which encircles turbine receptacle 90. Thus, it will be appreciated that ventricular assist device 10 utilizes a pair of turbine pump stages arranged as a series coupled pair. It will be equally well appreciated that each of the two pump stages operative within turbine receptacles 80 and 90 includes the combination of a turbine and a magnetic rotor. The resulting combinations are often referred to in the art as “frameless servo motors”. However, it will be apparent to those skilled in the art that other servo motor drive structures may be used to rotate the turbines without departing from the spirit and scope of the present invention. In accordance with an important aspect of the present invention, it will be noted that each of the pump stages may be independently operated and controlled as to speed and output. It will be further apparent to those skilled in the art that the use of pump stages in pairs provides a redundant pump stage arrangement that allows either pump stage to continue to provide blood flow despite a failure of either pump stage.

In operation, the series pair of pump stages of ventricular assist device 10 are driven by drive and control apparatus operative in combination to maintain blood flow. Accordingly, appropriate electrical signals are applied to drive coils 85 and 95 to induce rotation of magnetic rotors 56 and 66 which produces rotation of rotatably supported turbines 55 and 65 along with their respective magnetic rotors 56 and 66. As is described below in greater detail, it will be noted that the rotations of turbines 55 and 65 produce a straight-through flow path between input connector 13 and output connector 16. This straight-through flow path is enhanced by the venturi coupling between turbine receptacles 80 and 90 provided by tapered surfaces 81 and 91 together with surface 79. The purpose of the venturi coupling is to increase the flow velocity between the pump turbines and further enhance the blood flow between input connector 13 and output connector 16. As a result of the straight-through blood flow thus produced, areas of stagnation and blood pooling within the ventricular assist device are avoided. This, in turn, prevents blood coagulation within the ventricular assist device.

FIG. 7 sets forth perspective of an alternate embodiment of the present invention ventricular assist device generally referenced by numeral 110. By way of overview, ventricular assist device 110 differs from ventricular assist device 10 shown and described above in that the input connector and output connector are positioned on a common face of the device housing and are oriented in a common direction. To accommodate this connector orientation, the two turbine pumps are positioned in a side-by-side relationship aligned with the respective input and output connectors. The structure is completed by utilizing a curved generally U-shaped venturi coupling passage between the output of the turbine primp that receives blood flow from the input connector and the input to the turbine pump that pumps blood outwardly through the output connector. The result is an equivalent blood flow to the straight-through blood flow which characterizes ventricular assist device 10, described above.

More specifically, ventricular assist device 110 includes a housing 111 (seen in FIG. 8) that provides a protective enclosure for the operative mechanism within ventricular assist device 110. Housing 111 support a pair of end caps 112 and 114. End cap 112 further supports and input connector 113 while end cap 114 further supports an output connector 116. A pair of output pressure sensors 115 and 117 are supported upon output connector 116. In its preferred fabrication, housing 111 and end caps 112 and 114 together with connectors 113 and 116 are formed of a medically approved suitable molded plastic material or the like. By operation set forth below in greater detail, ventricular assist device 110 is operative to pump a flow of blood coupled to input connector 113 to exit at output connector 116.

FIG. 8 sets forth a side elevation view of ventricular assist device 110 which, as described above, defines a housing 111 supporting a pair of end caps 112 and 114. An input connector 113 is supported by end cap 112 while connector 116 is supported by end cap 114.

As is better seen in FIG. 10, conventional hoses 120 and 121 may be coupled to input connector 115 and output connector 116 respectively to provide blood flow which is pumped through ventricular assist device 110. It will be apparent to those skilled in the art that the small compact generally cylindrical shape of ventricular assist device 110 is well adapted to being implanted within a recipient's chest cavity in the manner shown in FIG. 10. It will be further apparent to those skilled in the art that the curved coupling passage structure utilized in ventricular assist device 10 which places input and output connections upon a common face of housing 111 may be particularly advantageous in certain implant environments and conditions. Conversely, it will be apparent to those skilled in the art that in other patient chest cavity environments a straight-through device structure such as ventricular assist device 10 may be advantageous. Accordingly, the present invention ventricular assist device presents alternate embodiments to suit the anticipated variation of chest cavity environments.

In operation, a pair of turbine, pumps, better seen in FIGS. 11 and 12 below, are operative within operative within ventricular assist device 110 to provide blood flow from input 115 through housing 111 and outwardly through output connector 116. As is set forth and described below in greater detail, a pair of turbine pumps arranged in a series configuration is operative to provide blood flow and due to the redundancy of turbine pumps also provides enhanced reliability. In the general design considerations under which ventricular assist device 110 is fabricated, either turbine pump has sufficient capability to be operated to produce a blood flow rate sufficient sustain the life of the ventricular assist device recipient. FIGS. 111 and 112 also shows the position of blood flow pressure sensors 114 and 117 upon output connector 116. As described below, pressure sensors 114 and 117 are operatively coupled to the controller shown in FIG. 11 to provide operational monitoring of ventricular assist device 110.

FIG. 9 sets forth an end view of ventricular assist device 110 showing housing 111 supporting an end cap 112 and input connector 113. FIG. 9 also shows the position of output connector 116 upon end cap 114 which are also supported by housing 111. The arrangement of housing 111, end caps 112 and 114 and input connector 113 and output connector 116 provide a blood flow produced by the redundant turbine pumps within ventricular assist device 110 that maintains both connectors on a common housing face while continuing to provide the venturi increased rate of blood flow similar to the above described straight-through blood flow. Pressure sensors 114 and 115 provide blood pressure information to be utilized by the microcontrollers (described below).

FIG. 10 sets forth a depiction of ventricular assist device 110 coupled to an illustrative human heart generally referenced by numeral 130. Human heart 130 includes a left ventricle 131 and an aorta 136. In the application of ventricular assist device 110 shown in FIG. 10, ventricular assist device 110 is functioning as a left ventricle assist device. Thus, the input of ventricular assist device 110 is coupled to the lower portion of left ventricle 131 at a coupling 132 using a hose 120. A hose 121 is coupled to the output connector of ventricular assist device 110 and is coupled to aorta 136 of heart 130 at a coupling 133. Couplings 132 and 133 are achieved utilizing conventional medical techniques to provide effective blood transfer and to prevent leakage and other problems. Similarly hoses 120 and 121 are fabricated of a medically of approved flexible hose construction and may be entirely conventional in fabrication.

In operation, heart 130 will be understood to be beating and attempting to pump blood from left ventricle 131 to aorta 136 and from there outwardly through the arteries of the patient's body. In a typical use of a ventricular assist device in the role of a left ventricle assist device shown FIG. 10, left ventricle 131 is, for some reason, underperforming and an adequate supply of blood is not being pumped into aorta 136. The benefit provided by ventricular assist device 110 in its role as a ventricle assist device is to provide a supplemental blood flow from left ventricle 131 through hoses 120 and 121 to aorta 136. As ventricular assist device 110 is operated, blood is pumped in the direction, indicated by arrow 122 which is carried by hose 135 to coupling 133 and thereafter flows into aorta 136. This is the basic left ventricle assist performance which greatly improves the blood supply and blood flow throughout the circulatory system the host patient, Thus, despite the underperformance of left ventricle 131, or other causes of heart underperformance, the host patient is sustained. In accordance with an important aspect the present invention ventricular assist device 110, blood flow velocity is maintained and blood pooling or stagnating is prevented throughout ventricular assist device 110 as well as hoses 120 and 121. The reliability of this vital blood flow is greatly improved due, in large part to the redundant dual turbine pumps arid their series arrangement provided by the invention. Even in the event of a failure of one of the turbine pumps, the remaining turbine pump continues and also increases output to compensate for the loss one turbine pump.

FIG. 11 sets forth a system diagram of the present invention ventricular assist device 110 together with supporting apparatus depicting the installation of ventricular assist device 110 within a host patient's body. In the situation represented in FIG. 11, ventricular assist device 110 has been implanted within a host patient's body and is operatively coupled to the heart in the manner set forth above in FIG. 10 to provide a left ventricle assist device. FIG. 11 further shows a microcontroller unit 140 also implanted within the host patient's body.

Microcontroller unit 140 is formed of a pair of fully redundant micro controllers 141 and 142. The redundancy of microcontrollers 141 and 142, with each able to fully support the operation of ventricular assist device 110 provides a further measure of reliability. Microcontroller unit 140 further includes conventional apparatus (not shown) for communicating to the exterior of the host patient's body in order to provide alarm condition information or other required maintenance or monitoring information to an external unit (not shown). As described above, ventricular assist device 110 includes a pair of flow sensors 115 and 117 situated at the output of ventricular assist device 110. Flow sensors 115 and 117 are coupled to redundant microcontrollers 141 and 142. Microcontroller 142 further includes additional sensors supported within ventricular assist device 110 for monitoring the performance of the servo drive apparatus therein.

A pair of battery units 150 and 160 are also implanted within the host patient. Battery unit 150 includes a secondary charging coil 151 coupled to a rectifier 152 which in turn is coupled to a battery 153. Battery unit 150 is coupled to microcontroller 141. Similarly, battery unit 160 includes a charging coil 161 coupled to a rectifier 162 which in turn is coupled to a battery 163. By way of further similarity, battery unit 160 is operatively coupled to microcontroller 142. Thus, microcontroller unit 140, ventricular assist device 110 and battery units 150 and 160 together with appropriate wire connections therebetween are implanted within a host patient body. For purpose of illustration, FIG. 11 shows body segments 118 and 119 which represent the skin and associated tissues of the host patient body beneath which battery units 150 and 160 are implanted. Preferably, units 150 and 160 are implanted near the host patient's midsection and preferably situated just beneath the patient's skin.

A charging belt 158 suitably configured to be worn by the host patient such as at or near the patient's waist supports a pair of charging units 155 and 156. Charging units 155 and 165 include respective primary charging coils 156 and 166. Coils 156 and 166 are coupled to source of alternating current power such as a conventional electrical outlet 145 via a conventional coupling adapter 146.

In operation, micro controllers 141 and 142 monitor sensors within ventricular assist device 110 and provide suitable operating power arid control to the servo drives supported therein (seen in FIG. 12). Microcontrollers 141 and 142 utilize batteries 153 and 163 for operative battery supply and for power to energize the servo drive apparatus within ventricular assist device 110. The operative power stored within batteries 153 and 163 is provided by inductive charging utilizing charging units 155 and 165. Thus, during convenient periods, the host patient utilizes charging belt 158 by coupling to power source 145 while wearing belt 158 such that primary charging coils 156 and 166 are positioned on the outside of body portions 118 and 119 respectively such that general alignment is obtained between primary charging coils 156 and 166 and secondary coils 151 and 161 respectively. Electrical power is then inductively coupled through body portions 118 and 119 to induce alternating current power within secondary coils 151 and 161. Rectifiers 152 axed 162 convert the alternating current induced in coils 151 and 161 to a direct current power suitable for charging batteries 153 and 163, in this manner, the user is able to replenish the battery energy as required by simply wearing charging belt 158 for a suitable time interval.

Micro controller unit 140 functions using a pair of fully-redundant fully-interconnected micro controllers 141 and 142, each having the complete capability to control and run the entire ventricular assist device 110 and it's monitoring and charging functions. Thus, microcontrollers 141 and 142 provide inputs for two batteries, inputs for multiple pressure and Hall effect servo sensors and systems capable of monitoring multiple battery charge levels and between batteries. The redundancy of microcontrollers 141 and 142 includes configuration of the system such that each microcontroller “sees” all its own inputs and also “sees” all inputs to the other micro controller. This redundancy includes each microcontroller being capable of making compensating performance adjustments to maintain envelope system performance. However, to avoid “hunting” between the redundant microcontrollers, it is preferred that small pressure variations of each pump be allowed before adjustment is made.

Micro controller unit 140 further includes communication capability, such as a wireless unit, to call, or text remote locations to indicate system anomalies, failures, operating conditions, battery charge levels and other conditions. In addition, micro controller unit 140 provides the capability to adjust each of micro controllers 141 and 142 based on pressure readings and to set and maintain preset maximum and minimum pressure envelopes. Micro controller unit 140 also pro the ability of replicating the pulsatile operation characteristic of a normal human heart by introducing pre-programmed increases and decreases of pump speed to create pressure surges and lulls.

FIG. 12 sets forth a section view of ventricular assist device 110 supported within housing 111. Housing 111 defines a common surface 167. Ventricular assist device 110 includes a pain of turbines 255 and 265 in a series arrangement. Turbines 255 and 265 are identical in fabrication and operation. Accordingly, the descriptions and operation that describe turbine 255 will be understood to be equally descriptive of and apply equally well to turbine 265. Turbine 255 is preferably fabricated to provide a helical blade progressive to form a helix. Turbine 255 further supports a cylindrical magnetic rotor 256 which is joined to the outer edges of turbine 255. Magnetic rotor 256 supports a plurality of permanent magnets and together with turbine 255 forms a single preferably integrally fabricated rotating component. Thus, for example, it will be recognized that while turbine 255 may be precision-fitted within magnetic rotor 256 due to the cylindrical structure of magnetic rotor 256 to form a single rotating unit. In the preferred fabrication of the present invention magnetic rotor 256 is integrally formed and molded with turbine 255. In either event, it will be recognized that the combined structure of turbine 255 and magnetic rotor 256 forms a single integral rotating unit. The combined structure of magnetic rotor 256 and turbine 255 are rotatably supported within the interior of housing 111 by a pair of bearing supports 257 and 267 positioned on each side of the rotating turbine element. The structure of bearing supports 257 and 267 includes center hubs 258 and 259 supported by a plurality of spokes 270, 271 and 272 (spoke 272 not shown). Within hub 258, a bearing cup 254 is supported which in turn receives one end of a bearing pin 253.

Bearing support 267 is identical to bearing support 257 and thus includes a center hub 259 which receives a bearing cup 264 and bearing pin 263. During assembly, bearing support 267 receives bearing cup 264 and is inserted in turbine receptacle 280 formed in housing 111. Thereafter, bearing pins 253 and 263 are inserted into the support shaft of turbine 255. The combined structure of turbine 255 supporting bearing pins 263 and 264 together with magnetic rotor 256 is then inserted into turbine receptacle 280. Bearing support 257 is then fitted within turbine receptacle 280 such that bearing pin 253 is received within bearing cup 254. Turbine 265 is assembled within turbine receptacle 290 in the same mariner. Once both turbine and magnetic rotor combinations have been assembled within housing 111, end caps 112 and 114 are joined to center housing 111 using an attachment such as thermal or sonic welding or other appropriate attachment. Once end caps 112 and 114 are assembled to housing 111, the structure of ventricular assist device 110 is complete and the resulting pump structure may be described.

More specifically, ventricular assist device 110 includes a housing 111 defining a pair of turbine receptacles 280 and 290. Receptacles 280 and 290 are aligned in a parallel relationship and define cylindrical receptacles. Turbine receptacles 280 and 290 are coupled by a generally U-shaped curved venturi coupling passage 281 formed by a curved narrowing tapered portion 281, a center venturi passage 279 and a curved tapered expanding portion 291. As a result, curved coupling passage 281 flows blood from the output of turbine 255 to the input of turbine 265 at an increased flow rate caused by the venturi effect.

Housing 111 further supports a generally cylindrical drive coil array 285 which encircles turbine receptacle 280. Drive coil assembly 285 is coupled to a motor controller such as controller 140 set forth above in FIG. 11. Similarly, housing 111 supports a corresponding drive coil 295 which encircles turbine receptacle 290. Thus, it will be appreciated that ventricular assist device 110 utilizes a pair of turbine pump stages arranged as a series coupled pair. It will be equally well appreciated that each of the two pump stages operative within turbine receptacles 280 and 290 includes the combination of a turbine and, a magnetic rotor. The resulting combinations are often referred to in the art as “frameless servo motors”. However, it will be apparent to those skilled in the art that other motor drive structures may be used to rotate the turbines without departing from the spirit and scope of the present invention. In accordance with an important aspect of the present invention, it will be noted that each of the pump stages may be independently operated and controlled as to speed and output. It will be further apparent to those skilled in the art that the use of pump stages in pairs provides a redundant pump stage arrangement that allows either pump stage to continue to provide blood flow despite a failure of either pump stage.

In operation, the series pair of pump stages of ventricular assist device 110 are driven by drive and control apparatus operative in combination to maintain blood flow. Accordingly, appropriate electrical signals are applied to drive coils 285 and 295 to induce rotation of magnetic rotors 256 and 266 which produces rotation of the rotatably supported turbines 255 and 265 along with their respective magnetic rotors 255 and 266. As is described below in greater detail, it will be noted that the rotations of turbines 255 and 265 produce an increased velocity flow path between input 113 and output 116. This flow path is enhanced by the venturi coupling between turbine receptacles 280 and 290 provided by narrowing portion 281 and expanding portion 291 venturi narrows 279. The purpose of the venturi coupling is to increase the flow velocity between the pump turbines and further enhance the blood flow between input 113 and output 116. As a result of the increased velocity blood flow thus produced, areas of stagnation and blood pooling, within the ventricular assist device are avoided. This, in turn, prevents blood coagulation within the ventricular assist device.

FIG. 13 sets forth a section view of a still further alternate embodiment of the present invention ventricular assist device. By way of overview, it will be apparent that the alternate embodiment shown in FIG. 13 is identical to the above described embodiments in that a pair of series coupled (with respect to blood flow) turbine pumps are operative to draw blood into an input connector, flow blood through a coupling passage, that preferably includes a venturi portion, and thereafter discharge the blood flow through and output connector. In the embodiment shown in FIG. 13 the input and output connectors are supported upon a common surface of the ventricular assist device housing and preferably emerge at approximately right angles to the common surface. The embodiment shown in FIG. 13 differs from the embodiments set forth above in that the coupling passage defines a generally V-shaped blood flow.

More specifically, FIG. 13 sets forth an alternate embodiment of the present invention ventricular assist device generally referenced by numeral 210. Ventricular assist device 210 is shown joined to a common surface 167 which will be understood to comprise a generally planar surface of the housing not shown) within which ventricular assist device 210 is enclosed. Thus, ventricular assist device 210 includes an input connector 211 defining an input connector axis 212 and an output connector 215 defining an output connector axis 216. Collectors 211 and 215 preferably define respective right angles 245 and 246 with respect to common surface 167. Ventricular assist device 210 includes a turbine 220 rotatably supported within a turbine receptacle 225. Turbine 220 is rotatably supported within turbine receptacle 225 and is rotatable about a turbine center axis 226. A magnetic rotor 221 is rotatably supported upon turbine 220 and is rotatable therewith. A drive coil assembly 222 is supported upon turbine receptacle 225 and provides electromagnetic energy which causes turbine 222 rotate and provide the above described blood pumping action. The structure and operation of turbine 220 is identical to the structure and operation of turbine 255 set forth above in FIG. 12.

Ventricular assist device 210 further includes a turbine 230 rotatably supported within turbine receptacle 235 and rotatable about an axis 236. Turbine 230 further includes a magnetic rotor 231. A drive coil assembly 232 encircles turbine receptacle 235 and provides electromagnetic energy which rotates turbine 230. As mentioned above with respect to turbine 220, it will be understood that turbine 230 together with its support structure and drive coil assembly are substantially identical to the above described turbine pumps, such as turbine pump 255 shown in FIG. 12.

Ventricular assist device 210 further includes a generally V-shaped coupling passage 240 which couples blood flow from the output of turbine 220 the input of turbine 230. Coupling passage 240 includes a narrowing portion 241 followed by a venturi portion 242 and an expanding portion 233. Venturi portion 242 performs the same increase of blood flow rate described above to avoid stagnation and blood clotting problems. To accommodate the substantially perpendicular angular relationship between input connector 211 and common surface 167, the interior end of input connector 211 defines an angle 217. Similarly, and for the same reason, output connector 215 includes an angle 218 at its interior end. Turbine axes 226 and 236 define a relative angle 247 therebetween which, in the preferred fabrication of the present invention embodiment of FIG. 13, is a right angle. However, it will be apparent to those skilled in the art, that the angular relationship between the respective axes of turbines 220 and 230 may define different angles without departing from the spirit and scope of the present invention.

In operation, blood flows inwardly through input connector 211 through turbine 220 in the direction indicated by arrow 238. Thereafter, blood flows through venturi portion 242 of coupling passage 240 in the direction indicated by arrow 239. Blood then flows through turbine 230 outwardly, the direction indicated by arrow 248, through output connector 215.

What has been shown is a dual stage redundant impeller ventricular assist device. Within the housing of the device, a pair of electrically driven impeller drive motors facilitate the pumping of blood from one portion of the circulatory system to another portion of the circulatory system, such as from the lower left ventricle to the aorta. The use of dual pump drives for the pump turbines configured to provide complete pump redundancy should a pump fail. In such case, the remaining operative motor/pump drives the turbines coupled thereto with sufficient capability and circulation to, maintain life in the recipient until remedial inter intervention may be performed. The output from the pump support a sensor coupled to a dual microprocessor drive controller. Each processor drive controller is operative coupled to both of the redundant pump drive motors. Sensors are also provided to monitor the operation of each pump system. A pair of battery modules each including an inductively coupled charging device are implanted within the patient abdomen and operatively coupled to the processor controller and the drive motors. A pair of inductive battery charging modules are supported upon an abdominal belt and coupled to a source of operative electrical power. Battery charging is accomplished by inductive coupling through the body tissue between the external charging modules and the implanted battery and charger apparatus. The dual redundant micro controller is also implanted within the recipient's body.

FIG. 14 sets forth a section view of another embodiment of a ventricular assist device 310. As described above ventricular assist device 310 includes a generally cylindrical housing 311 supporting a pair of end caps 312 and 314. End caps 312 and 314 support an input coupler 313 and an output coupler 315, respectively. Input coupler 313 further defines an input passage 320 extending through input coupler 313 and end cap 312. Correspondingly, output coupler 315 defines an output passage 321 extending through output coupler 315 and end cap 314. Housing 311 further defines a pump receptacle 322 within which a turbine pump 330 is supported. Housing 311 further defines a pump receptacle 323 within which a turbine pump 350 is supported. Pump receptacles 322 and 323 are coupled by a venturi passage 324 such that a continuous blood flow passage between input passage 320 of input coupler 313 and output passage 321 of output coupler 315 is formed.

Turbine pump 330 includes a turbine impeller 331 supported upon an arbor 332. Turbine pump 330 further includes a generally cylindrical rotor 333 which is joined to the outer edges of turbine impeller 331 and is therefore rotatable therewith. A cylindrical isolator 335 is preferably formed of a suitable glass material and is fixed to the interior of pump receptacle 322 of housing 311. Isolator 335 is spaced from rotor 333 such that an air gap 334 is formed between rotor 333 and isolator 335. A motor core 336 encloses isolator 335 and is similarly fixed within pump receptacle 322. Turbine pump 330 further includes an outer core ring 337 encircling the outer surface of motor core 336. Turbine pump 330 further includes windings 340 and 341 on either side of outer core ring 337 which similarly encircle motor core 336.

Turbine pump 330 further includes a deswirler 342 having a deswirler body 343 which supports a plurality of curved deswirler vanes 344. Deswirler vanes 344 extend from deswirler body 343 and are fixed within the interior of venturi passage 324 of housing 311 and secure the position of deswirler 342 therein. Deswirler body 343 further supports a bushing 345 which in turn receives the remaining end of arbor 332. A flared portion 347 is formed between the end of arbor 332 and the end of bushing 345 to provide a thrust load carrying surface which maintains arbor 332 within bushing 345. Arbor 332 is rotatable within bushing 345 such that a bearing is formed therebetween. In the preferred fabrication of the present invention, arbor 332 and bushing 345 are made of a jewel bearing material such as sapphire, or the like.

Turbine pump 350 is virtually identical to turbine pump 330 and thus includes a turbine impeller 351 supported upon an arbor 352. Turbine pump 350 further includes a generally cylindrical rotor 353 which is joined to the outer edges of turbine impeller 351 and is therefore rotatable therewith. A cylindrical isolator 355 is preferably formed of a suitable glass material and is fixed to the interior of pump receptacle 323 of housing 311. Isolator 355 is spaced from rotor 353 such that an air gap 354 is formed between rotor 353 and isolator 355. A motor core 356 encloses isolator 355 and is similarly fixed within pump receptacle 323. Turbine pump 350 further includes an outer core ring 357 encircling the outer surface of motor core 356. Turbine pump 350 further includes windings 360 and 361 on either side of outer core ring 357 which similarly encircle motor core 356.

Turbine pump 350 further includes a deswirler 362 having a deswirler body 363 which supports a plurality of curved deswirler vanes 364. Deswirler vanes 364 extend from deswirler body 363 and are fixed within the interior of pump receptacle 323 of housing 311 and secure the position of deswirler 362 therein. Deswirler body 363 further supports a bushing 365 which in turn receives the remaining end of arbor 352. A flared portion 367 is formed between the end of arbor 352 and the end of bushing 365 to provide a thrust load carrying surface which maintains arbor 352 within bushing 365. Arbor 352 is rotatable within bushing 365 such that a bearing is formed therebetween. In the preferred fabrication of the present invention, arbor 352 and bushing 365 are made of a jewel bearing material such as sapphire, or the like.

In operation, ventricular assist device 310 is positioned within a patient's circulatory system in the manner described above utilizing suitable connecting apparatus (not shown) for securing input coupler 313 and output coupler 315 to the patient's blood vessels. As is also described above, a power and control system (not shown) is operatively coupled to the electric motor windings within turbine pumps 330 and 350 to provide energizing and control signals for operation of the electric motors therein. As turbine impellers 331 and 351 are caused to rotate, a flow of blood is induced which flows into input passage 320 of input coupler 313 and thereafter through turbine impeller 331 and deswirler 342 through Venturi passage 324 and into pump receptacle 323. This flow continues increased by the rotation of turbine impeller 351 and the resulting blood flow continues outwardly from pump receptacle 323 past deswirler 362 exiting through output passage 321 of output coupler 315. In accordance with an important aspect of the present invention the blood flows induced by the rotations of turbine impellers 331 and 351 immediately flows through the structures of deswirlers 342 and 362, respectively. It will be noted that deswirler vanes 344 of deswirler 342 are oppositely curved with respect to the vanes of turbine impeller 331. This relationship allows deswirler 342 to overcome or straighten the rotational vortex turbulence induced within the blood low as turbine impeller 331 is rotated. This operation is often referred to in the art as “flow straightening”. The blood flow leaving deswirler 342 and entering Venturi passage 324 is substantially free of rotational vortex turbulence. A similar oppositely curved relationship exists between deswirler vanes 364 and turbine impeller 351. Accordingly, deswirler 362 is similarly operative to ensure that the outward blood flow through output passage 321 of output coupler 315 is also substantially free of rotational vortex turbulence.

It has been determined that the size of gap 346 between turbine impeller 331 and deswirler 342 and the size of gap 366 between turbine impeller 351 and deswirler 362 are critical to the proper operation of flow straightening. Accordingly, gaps 346 and 366 are preferably maintained at 0.5 millimeters.

It will be noted that ventricular assist device 310 is shown having a pair of redundant turbine pump and deswirler stages. It will be recalled that this greatly increases the reliability of the ventricular assist device. It will also be apparent to those skilled in the art that redundance may be further enhanced by using a greater plurality of turbine pump and deswirler stages, such as three or four or more, without departing from the spirit and scope of the present invention. While not shown in FIG. 14, it will be understood that in a typical application, ventricular assist device 300 is coupled to a blood circulatory system within a host patient by suitable blood vessel connections to the input coupler 313 and output coupler 316.

FIG. 15 sets forth a section view of another embodiment of a ventricular assist device 400. Ventricular assist device 400 includes a generally U-shaped housing 401 supporting an input coupler 402 and an output coupler 404, respectively. Input coupler 402 further defines an input passage 403 extending through input coupler 402. Correspondingly, output coupler 404 defines an output passage 405 extending through output coupler 404. Housing 401 further defines a pump receptacle 422 within which a turban pump 430 is supported. Housing 401 further defines a pump receptacle 423 within which a turbine pump 450 is supported. Pump receptacles 422 and 423 are coupled by a Venturi passage 424 such that a continuous blood flow passage between input passage 403 of input coupler 402 and output passage 405 of output coupler 404 is formed.

Turbine pump 430 includes a turbine impeller 431 supported upon an arbor 432. Turbine pump 430 further includes a generally cylindrical rotor 433 which is joined to the outer edges of turbine impeller 431 and is therefore rotatable therewith. A cylindrical isolator 435 is preferably formed of a suitable glass material and is fixed to the interior of pump receptacle 422 of housing 401. Isolator 435 is spaced from rotor 433 such that an air gap 434 is formed between rotor 433 and isolator 435. A motor core 436 encloses isolator 435 and is similarly fixed within pump receptacle 422. Turbine pump 430 further includes an outer core ring 437 encircling the outer surface of motor core 436. Turbine pump 430 further includes windings 440 and 441 on either side of outer core ring 437 which similarly encircle motor core 436.

Turbine pump 430 further includes a deswirler 442 having a deswirler body 443 which supports a plurality of curved deswirler vanes 444. Deswirler vanes 444 extend from deswirler body 443 and are fixed within the interior of Venturi passage 424 of housing 401 and secure the position of deswirler 442 therein. Deswirler body 443 further supports a bushing 445 which in turn receives the remaining end of arbor 432. A flared portion 447 is formed between the end of arbor 432 and the end of bushing 445 to provide a thrust load carrying surface which maintains arbor 432 within bushing 445. Arbor 432 is rotatable within bushing 445 such that a bearing is formed therebetween. In the preferred fabrication of the present invention, arbor 432 and bushing 445 are made of a jewel bearing material such as sapphire, or the like.

Turbine pump 450 is virtually identical to turbine pump 430 and thus includes a turbine impeller 451 supported upon an arbor 452. Turbine pump 450 further includes a generally cylindrical rotor 453 which is joined to the outer edges of turbine impeller 451 and is therefore rotatable therewith. A cylindrical isolator 455 is preferably formed of a suitable glass material and is fixed to the interior of pump receptacle 423 of housing 401. Isolator 455 is spaced from rotor 453 such that an air gap 454 is formed between rotor 453 and isolator 455. A motor core 456 encloses isolator 455 and is similarly fixed within pump receptacle 423. Turbine pump 450 further includes an outer core ring 457 encircling the outer surface of motor core 456. Turbine pump 450 further includes windings 460 and 461 on either side of outer core ring 457 which similarly encircle motor core 456.

Turbine pump 450 further includes a deswirler 462 having a deswirler body 463 which supports a plurality of curved deswirler vanes 464. Deswirler vanes 464 extend from deswirler body 463 and are fixed within the interior of pump receptacle 423 of housing 401 and secure the position of deswirler 462 therein. Deswirler body 463 further supports a bushing 465 which in turn receives the remaining end of arbor 452. A flared portion 467 is formed between the end of arbor 452 and the end of bushing 465 to provide a thrust load carrying surface which maintains arbor 452 within bushing 465. Arbor 452 is rotatable within bushing 465 such that a bearing is formed therebetween. In the preferred fabrication of the present invention, arbor 452 and bushing 465 are made of a jewel bearing material such as sapphire, or the like.

In operation, ventricular assist device 400 is positioned within a patient's circulatory system in the manner described in the above-referenced incorporated co-pending patent application utilizing suitable connecting apparatus (not shown) for securing input coupler 402 and output coupler 404 to the patient's blood vessels. As is also described in the above-referenced incorporated co-pending patent application, a power and control system (not shown) is operatively coupled to the electric motor windings within turbine pumps 430 and 450 to provide energizing and control signals for operation of the electric motors therein. As turbine impellers 431 and 451 are caused to rotate, a flow of blood is induced which flows into input passage 403 of input coupler 402 and thereafter through turbine impeller 431 and deswirler 442 through Venturi passage 424 and into pump receptacle 423. This flow continues increased by the rotation of turbine impeller 451 and the resulting blood flow continues outwardly from pump receptacle 423 past deswirler 462 exiting through output passage 405 of output coupler 404. In accordance with an important aspect of the present invention the blood flows induced by the rotations of turbine impellers 431 and 451 immediately flows through the structures of deswirlers 442 and 462 respectively. It will be noted that deswirler vanes 444 of deswirler 442 are oppositely curved with respect to the vanes of turbine impeller 431. This relationship allows deswirler 442 to overcome or straighten the rotational vortex turbulence induced within the blood low as turbine impeller 431 is rotated. This operation is often referred to in the art as “flow straightening”. As a result, the blood flow leaving deswirler 442 and entering Venturi passage 424 is substantially free of rotational vortex turbulence. A similar oppositely curved relationship exists between deswirler vanes 464 and turbine impeller 451. Accordingly, deswirler 462 is similarly operative to ensure that the outward blood flow through output passage 405 of output coupler 404 is also substantially free of rotational vortex turbulence.

It has been determined that the size of gap 446 between turbine impeller 431 and deswirler 442 and the size of gap 466 between turbine impeller 451 and deswirler 462 are critical to the proper operation of flow straightening. Accordingly, gaps 446 and 466 are preferably maintained at 0.5 millimeters.

What has been shown is a ventricular assist device having a pair of turbine pumps positioned in a series flow relationship within the blood flow passage of a housing. Each turbine pump is enhanced by a deswirler positioned downstream of the turbine pump impellers. The deswirler acts to reduce or substantially eliminate rotational turbulence or vortex turbulence within the blood flow induced by the rotating turbine impellers.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. 

1. A ventricular assist device comprising: a housing having an input, an output and a fluid passageway extending from said input to said output; a first turbine pump within said fluid passageway operative to flow blood through said fluid passageway; a second turbine pump within said fluid passageway operative to flow blood through said fluid passageway; a venturi portion within said fluid passageway between said first and second turbine pumps; and at least one set of deswirler vanes in said fluid passageway positioned downstream of at least one of said first and second turbine pumps.
 2. The ventricular assist device of claim 1, wherein at least one of said first and second turbine pumps further comprises: a turbine impeller supported upon an arbor; a rotor joined to the outer edges of said turbine impeller and rotatable therewith; a cylindrical isolator formed of a glass material and fixed to the interior of a pump receptacle of said housing.
 3. The ventricular assist device of claim 1, wherein said first and said second turbine pumps are redundant whereby if one of said pumps fails said other pump increases its flow capacity.
 4. A ventricular assist device comprising: a housing having an input, an input turbine receptacle, an output, an output turbine receptacle and a coupling passage between said input turbine receptacle and said output turbine receptacle, said input, said input turbine receptacle, said output, said output turbine receptacle and said coupling passage being generally coaxial; a turbine pump supported within said input turbine receptacle operative to flow blood from said input through said coupling passage and through said output; and at least one additional turbine pump supported within said output turbine receptacle operative to flow blood from said input through said coupling passage and through said output; and at least one set of deswirler vanes in said coupling passage positioned downstream of at least one of said turbine pumps.
 5. A ventricular assist device comprising: a housing having an input configured to be coupled to a ventricle of a human heart, an input turbine receptacle, an output configured to be coupled to aorta of a human heart, an output turbine receptacle and a coupling passage between said input turbine receptacle and said output turbine receptacle, said input, said input turbine receptacle, said output, said output turbine receptacle and said coupling passage being generally coaxial; a first turbine pump supported within said input turbine receptacle operative to flow blood from said input through said coupling passage and through said output; a first deswirler fixed within said first turbine receptacle having a first plurality of deswirler vanes; a second turbine pump supported within said output turbine receptacle operative to flow blood from said input through said coupling passage and through said output; and a second deswirler fixed within said second turbine receptacle having a second plurality of deswirler vanes.
 6. A ventricular assist device comprising: a housing sized to be implantable within a human recipient's chest, said housing having an input, a plurality of turbine receptacles and a plurality of coupling passages therebetween, said plurality of turbine receptacles including an input turbine receptacle and an output turbine receptacle; a plurality of turbine pumps each supported within one of said turbine receptacles operative to flow blood from said input through said coupling passages to maintain adequate blood circulation to sustain normal life functions; and a plurality of deswirlers each fixed within an associated turbine receptacle and each having a plurality of deswirler vanes.
 7. The ventricular assist device of claim 1, further comprising a gap between said turbine pump and said deswirler about 0.5 mm wide.
 8. The ventricular assist device of claim 1, further comprising at least one flow sensor positioned at said outlet of said housing.
 9. The ventricular assist device of claim 2, wherein said isolator is spaced from said rotor by an air gap between said rotor and said isolator.
 10. The ventricular assist device of claim 2, further comprising: a motor core enclosing said isolator, said motor core fixed within said pump receptacle.
 11. The ventricular assist device of claim 2, said turbine pump further comprising: an outer core ring encircling the outer surface of said motor core; and windings on either side of said outer core ring which encircle said motor core.
 12. The ventricular assist device of claim 2, said turbine pump further comprising: sapphire bearings between said turbine impeller and said arbor.
 13. The ventricular assist device of claim 1, further comprising: an implantable microcontroller unit including a pair of fully redundant micro controllers able to fully support the operation of said first and second turbines of said ventricular assist device, said implantable microcontroller electrically coupled to said ventricular assist device.
 14. The ventricular assist device of claim 13, further comprising; a pair of flow sensors at the output of said ventricular assist device, said flow sensors electrically coupled to said microcontrollers.
 15. The ventricular assist device of claim 13, further comprising: at least one implantable battery unit including a secondary charging coil coupled to a rectifier coupled to a battery, said at least one battery unit coupled to said implantable microcontroller and said first and second turbines.
 16. The ventricular assist device of claim 13, wherein said implantable microcontroller independently controls each of said first and second turbines speed and output.
 17. The ventricular assist device of claim 1, wherein said implantable microcontroller independently controls each of said first and second turbines and provides redundant turbine control to control one of said first and second turbines to continue to provide blood flow despite a failure of the other of said first and second turbines.
 18. The ventricular assist device of claim 13 wherein said microcontroller further includes wireless communication capability to call or text a remote location to indicate system anomalies, failures, operating conditions, battery charge levels or operating conditions.
 19. The ventricular assist device of claim 1, wherein said microcontroller controls said redundant micro controllers and thereby said first and second turbines based on sensor readings from said pair of flow sensors to maintain blood flow within a preset maximum and minimum pressure envelope and replicate the pulsatile characteristic of a normal human heart by introducing pre-programmed increases and decreases of turbine speed to create pressure surges and lulls.
 20. The ventricular assist device of claim 1, wherein said first turbine includes a plurality of curved vanes and said at least one set of deswirler vanes are oppositely curved with respect to said curved vanes of said first turbine. 